1. Field Observations

Welcome back! If you're new to our mailing list, each week I distribute this newsletter to update the agricultural community of what's happening in our 8-county region with regards to field conditions, insect pests, diseases, and weed monitoring, and cropping activities in field crops (grains and forages).

I've seen a few fields planted with corn and soybeans, but I anticipate many more acres to be planted after this rainy stretch subsides. Winter grains are looking fantastic so far, so hopefully growers have been able to make the necessary weed control and fertilizer applications. Alfalfa and grass hay crops are chugging along, so with that in mind…:

This time of year, the CNY regional Dairy, Livestock, and Field Crops team measures the heights of alfalfa crops to inform farmers of how near their field may be to peak yield and quality. We use alfalfa heights to estimate NDF and predicted harvest date. Most fields are still too short to predict harvest date, but keep in mind that if alfalfa is 10" tall, nearby grass crops are very close to peak maturity for dairy!

2. First Cutting Forage Quality

Alfalfa height is a reliable indicator of NDF values in the field, so we use alfalfa height to predict Neutral Detergent Fiber (NDF) for alfalfa, mixed alfalfa/grass, and pure grass stands. When using alfalfa and grass height as an indicator of NDF content, in general:

Begin cutting 100% grass stands when nearby alfalfa is 14" tall to achieve the desired 50% NDF.

Begin cutting 50/50 alfalfa/grass stands when nearby alfalfa is 22" tall for the desired 44% NDF.

Begin cutting 100% alfalfa stands when alfalfa is 28" tall for the desired 40% NDF.

To achieve the desired NDF it is necessary to begin cutting at NDF values slightly lower than the desired value assuming some harvest and storage losses (which the above alfalfa height values reflect). For example 28 inch tall alfalfa is closer to 38% NDF but you will need to start then to end up at 40% NDF.

Predicted days to cut are based on daily NDF increases for grasses (1%), 50/50 mixed stands of (0.8%), and alfalfa (0.5%). Typically, NDF increases about 0.8 to 1.2/day for grasses and 0.4 to 0.7/day in alfalfa, expecting the lower end of that range in cooler weather and the higher end in warm. See the following fact sheet for more details: Predicting Spring Fiber Content of Forages.

Always check your fields to verify your heights and conditions! Remember that these predicted harvest dates are not set in stone, and will fluctuate as we go along. And they may creep up on us - especially since the fields are getting a lot of moisture now, and the temperature is only going up!

(Click on each table to enlarge.)

If your location is not listed but you know the height of your alfalfa, this chart is for you. As of MAY 2, 2025, if your alfalfa is:

See you in the field!